Short of restarting the PI Update Manager subsystem, you can't manually remove this signup. The Update Manager automatically cleans up orphaned or lost signups after a short period of time. With the point deleted, the update producer (presumably the snapshot subsystem) will no longer be sending updates to the queue, and the consumer that created the signup will not be retrieving anything, so I would expect this signup to eventually become classed as 'lost' and then cleaned up.

Restarting the PI Update Manager subsystem is not an option in my customer's Production system.

Thanks for this remark: "Update Manager automatically cleans up orphaned or lost signups after a short period of time"

1. Do you know where is this "short period of time" Configured or is it a known hardcoded time period?

2. Does the "Update Manager" update or trigger something in the system, that I can monitor to see that it "cleaned the orphaned signups" ?

3. What I was expecting from OSI-Soft is to give us the option in the AFSDK to request a "PIPE Refresh" from the "Update Manager" so that we know that all it's pipes are good ones and all the "orphaned SignUps".

Timeout periods such as mentioned are typically configured via PI Tuning Parameters. Looking through the parameters for the Update Manager, I believe that Update_PersistentConsumerTimeout is the parameter that would likely come into play here. On my test system, this default value for this parameter is 86400 seconds. So I would have expected that point signup to be removed no more than a day after it became inactive. Observations on my own test system (for an unrelated purpose, but with a similar scenario) showed that inactive signups were removed much sooner than that (< 1 hour). Unfortunately I don't know the internals of this subsystem as well as I once did, but I'd be surprised if the orphaned point signup persists beyond a day.

You mentioned that you are monitoring the snapshots of these points with some custom code. Is this application the same one that created the datapipe with these signups in the first place? Are you able to restart this application? Doing so should clean up the signups, as PIDataPipe implements IDisposable (assuming you created the datapipe in a using block), and this should properly close any subscriptions with the Update Manager.

"Does the "Update Manager" update or trigger something in the system, that I can monitor to see that it "cleaned the orphaned signups" ?" - I don't think so, at least not that I have seen.

There's a number of similar questions in these forums about limits on the number of datapipes, performance etc. To get a feel for these, take a look at the information in this thread and this thread. In a nutshell, data throughput rate is the factor to consider more than point or attribute count.